VAIO PCVR526DS

I am trying to help a friend update his computer.I am very nervous about proceeding.Sony
is not known for its support.This particular
motherboard is made by ASUS and is a P2B-AE which
does not show up on the ASUS website.This computer
needs a BIOS upgrade, but SONY no longer supports
this unit.As far as I can tell, it never has.I went to the VAIO VILLAGE and one person used the
latest bios from a VAIO547 to update his pcvr526ds. He says it seems to work OK. Has anyone out there in computerland ever attempted
this?The present bios does not support large drives.Hope someone can help!